Treatment shows combination therapy leads to long-term remission in follicular non-Hodgkin's lymphoma

10-03-2006

Patients with a form of lymphatic cancer who received a new combination of chemotherapy and targeted radiation (radio immunotherapy) lived significantly longer than patients treated with standard chemotherapy alone on previous trials.

Five-year follow-up data from the Phase II trial was published in the Journal of Clinical Oncology.

Patients in the trial, known as S9911, were being treated for advanced follicular non-Hodgkin's lymphoma, a form of cancer that affects the blood, bone marrow and lymphatic tissues.

The long-term follow-up data from the Phase II clinical trial shows that five years after the new treatment, 87% of the patients survived and 67% of the patients survived without their disease progressing. In comparison, using historical data, only 64% were still alive and 44% survived without disease progression after five years on the standard chemotherapy treatment.

The new treatment piggy-backs onto the standard treatment by delivering a one-two punch to the cancer cells, explained Oliver Press, M.D., who led the study for the Southwest Oncology Group. The standard therapy uses a combination of four chemotherapy drugs known as CHOP - cyclophosphamide, doxorubicin, vincristine and prednisone.

Patients in the trial received six 21-day treatment cycles of CHOP. Those who tolerated the treatment without progression were given the new treatment, tositumomab and Iodine-I 131 tositumomab. Tositumomab is an antibody developed in mice, which binds to the CD20 antigen, found on the surface of normal and malignant B lymphocytes. The radiolabeled antibody delivers Iodine-I 131 directly to the cancer cells. Tositumomab/Iodine-I 131 tositumomab is marketed under the trade name Bexxar by GlaxoSmithKline.

The initial success of the SWOG Phase II trial, known as S9911, prompted SWOG to open a Phase III intergroup trial in 2001 known as S0016. The Phase III trial is still open for registration to patients who have never been treated for follicular non-Hodgkin's lymphoma and whose disease expresses the CD20 antigen. The Cancer and Leukemia Group B and Eastern Cooperative Oncology Group are also participating in this study.

The Phase III study compares CHOP plus BEXXAR to CHOP plus a different targeted antibody, Rituximab. The study was initially designed to compare three types of treatment - CHOP, CHOP plus Rituximab, and CHOP plus Tositumomab and Iodine-I 131.

However, the CHOP-only arm of the study was closed Dec. 15, 2002, based on results from several completed clinical trials that demonstrated significantly improved response rates and progression-free survival in the CHOP-plus-Rituximab arm compared to CHOP alone, making CHOP plus Rituximab the new standard therapy.

The 17 patients on the Southwest Oncology Group trial S0016 were accrued to the CHOP-only arm before the survival data comparing the CHOP-plus-Rituximab arm and the CHOP-only arm were known.

"Now the goal is to determine which antibody - rituximab or the radiolabeled tositumomab antibody - produces the best results when combined with CHOP," Press said. "This study is currently open to accrual and we encourage treating physicians and their patients to join us in completing this important clinical trial." He noted that another radiolabeled antibody, ibritumomab tiuxetan (Zevalin), is being studied by other investigators.

Southwest Oncology Group is a cooperative research group.

This article was prepared by Biotech Business Week editors from staff and other reports. Copyright 2006, Biotech Business Week via NewsRx.com.